Output order on Radeon X1950 [patch]

Jörg Walter jwalt at garni.ch
Tue Oct 21 11:52:27 PDT 2008

On Tuesday, 21. October 2008, Alex Deucher wrote:
> On Tue, Oct 21, 2008 at 1:43 PM, Jörg Walter <jwalt at garni.ch> wrote:
> > On Tuesday, 21. October 2008, you wrote:
> >> The order is arbitrary and changing it would break existing setups.
> >> Also, the radeon driver has had randr 1.2 support for much longer than
> >> radeonhd or fglrx.
> >
> > Still, all other drivers, including Windows, agree on "first" vs.
> > "second" output connector, regardless of RandR 1.2 or not -- point is, if
> > I switch drivers or OS, my primary display suddenly isn't primary
> > anymore, kdm appears on the wrong screen, as does the taskbar or yakuake.
> Then move the taskbar or kdm to the screen you want it on.  No cable
> switching needed.  Gnome at least will even remember how you've
> configured things, I'd imagine kde will do so as well.

Only when I switch drivers again, I need to move things around again. Not to 
mention that kdm simply appears on the first screen, with no obvious way to 
move it (might exist, but not in the GUI)

> > Really, should I switch my monitor cables every time I switch from/to
> > radeon driver, like after running Windows or maybe using fglrx for a
> > gaming session?
> no need to switch cables as I said above.

My point stays valid, as you can see.

> > IMHO this is far worse breakage than a one-time setup change for a driver
> > that claims it is still under development. My patch even avoids renaming
> > devices,
> And what if another driver decides to change their order at some point?

I'd think the behavior provided by the manufacturer (i.e., AMD/ATI) should be 
considered canonical, unless there is a significant advantage in diverging 
(which isn't, in this case). For the highly unlikely case that the official 
drivers should change behaviour, feel free to revive this discussion.

> > so no setups can break except those that rely on the allegedly arbitrary
> > order.
> Changing the order will break all existing dualhead layouts that have
> been in use for the past couple years requiring all those users to
> switch their cables or re-write their configs.

Uhm... with the current transition to RandR 1.2 every setup will break 
anyways. There is no RandR 1.2 configuration that has been in use for years. 
Anyone who has such a long standing X (+Xinerama) configuration has a high 
chance that he will need to change it anyways. And we're still talking about a 
driver that announces being "in development" on startup, so users are already 

Really, it means a one-time inconvenience for people who already have a high 
chance of needing to change their configuration due to the move to RandR 1.2, 
and who know that they are using beta software. They gain consistent behaviour 
across all drivers on Linux and Windows. I even provided a patch.


More information about the xorg-driver-ati mailing list